1. Field of the Invention
The present invention relates to a process and a device to dry a drying room.
2. Prior Art
The German Patent DE 36 44 077 A1 and EP0043 361 A1 reveal a process and a device to dry wet laundry. Such systems are however technically seen as very complicated and the drying process as very time consuming. This is so because the high inlet volume flow is difficult to handle and because the non condensable gases in the inlet volume flow, such as air or the like, are difficult to extract. Additionally the energy consumption is very high.
Another known drying process uses a rotary sliding vane type compressor or a liquid seal pump to pump condensable gases as well as non condensable gases. However, it is importent that the temperature of the liquid ring is considerably lower than the temperature of the inlet gas otherwise the liquid of the liquid ring of the pump will evaporate due to the fact that the boiling pressure is reached. At this point practically no compression takes place. If the temperature of the liquid ring or the water jet considerably below the temperature of the condensing fluid, good results are achieved.
With a gas ballast device in a rotary sliding vane type compressor the working fluid can attain higher pressure ratios. The disadvantage is a lower efficiency and the following condensation is more difficult due to the lack of non condensable gases.
Another generally known method to evacuate a room filled with condensable and non condensable gases is the use of a gas jet pump for the first stage of compression to avoid cavitation. The disadvantage is the necessity of a gas source and the mixture of condensable and non condensable fluids.
A general problem is the very high inlet volume flow of the gas mixture at the beginning of compression. It is possible to use a roots pump or a rotary sliding vane type compressor. However, this is an expensive investment as a large space for a big pump is needed.
Further, it is generally known from the publication, H. D. Baehr, "Thermodynamik", Springer Verlag 4th edition, 1978, pages 289-292, and especially FIG. 6.48, to approximate a compression process to the Carnot cycle by intermediate cooling.
Therefore it is an object of the present invention to have a process and a device to dry a drying room by means of a few small elements with the need of little energy.